Rock-drilling motor



C. H. ALLEN ROCK DRILLING MOTOR Filed April '7. 1922 motor cylinder of aPatented Aug. 7, 1928.

- CHARLES H. ALLEN, OF CLARE-MONT, NEVT HAMPSHIRE, ASSIGNOR TO SULLIVANMACHINERY COMPANY, A COREGBATION OF MASSACHUSETTS.

ROCK-DRILLING MOTOR.

Application filed April 7, 1922. Serial No. 550,460.

My invention relates to motors and more particularly to rock drillingmotors of the percussive type.

An object of my invention is to provide an improved motor. Anotherobject of my invention is .to provide an improved motor in which extremerapidity of reciprocation may be obtained. A further object of myinvention is to provide an improved motor for rock drilling purposes inwhich by reason of increased speed and power of reciprocation of thepiston, the speed of drilling may be very materially increased. A stillfurther object of my invention is to provide an improved valve mechanismfor motors and especially adapted for rock drilling motors. Otherobjects and advantages of my invention' will, however, hereinafter morefully appear.

In the accompanying drawings I have shown for purposes of illustrationone form which my invention may In these dratwings,.

'Fig. 1 is a, central vertical longitudinal section through the valvemechanism and motor in which the il lustrative embodiment of myinvention is incorporated.

Fig. 2 is a similar view with the moving parts of the 'motor shown indifferent position.

In the form ofmy invention shown for purposes of illustration in theaccom-v panying drawings, I provide a cylinder 1 in whose bore 2 apiston 3 is reciprocable, this piston having a striking bar 1: of wellknown construction connected thereto. The opposite ends of. the cylinderare closed by heads 5 and 6 and from the head 6 a suitable rifle bar 7projects, this rifle bar extending into this piston and controlling. itsmove ment.

For the purpose of causing reciprocation of the piston, suitabledistributing passages 9 and 10 'leadto points adjacent the opposite endsof the cylinder, the passage 9 leading to the front end of the cylinder,whilethepassage 10 leads to the rear end thereof. The supply and exhaustof fluid through the dis tributing passages 9 and 10is controlled by .avalve mechanism generally indicated by assume in practice.

11 and comprising able bushings 13 are arranged in such manner as toform a chamber having end portions 14 of smaller diameter than itscentral portion 15. The passages 9 and 10 communicate with the valvechamber adjaccnt the ends of the central enlarged bore 15, the passage 9communicating as at 16 and the passage 10 as at 17, there being annulargrooves 18 formed adjacent the shoulders 19 which constitute the ends ofthe enlarged bore 15, which grooves communicate with the ports 16 and 17and so with the passages 9 and 10. Adjacent the remote ends of thesmaller portions 14, ports 20 and 21 connect throwing passages 22 and9.3 with the valve chamber, these passages at their opposite endscommunicating with the bore of the cylinder 2 by a plurality of ports,the passage 22 communicating with the cylinder at a point spaced arelatively short distance from the position of the rear end of thepiston when the latter is in its steel engaging position by a port 2iand also having a smaller port 25 connected with the passage 22 by apassage the bore of the cylinder at a point materially nearer the rearend thereof. The passage 23 opens into the bore of the cylinder torwardof the middle thereof, by a pair of ports 27 and 28 which passage 29,the port 27 being the main throw ing port and the port 28which ismaterially smaller, being spaced a substantial distance nearer the frontend of the cylinder. Inter-- mediate the ports 16 and 20 and 17 and 21respectively in the valve chest, there are formed annular grooves 30 and31, which grooves communicate by ports 32- and 33 with an exhaustpassage 3t formed in a box like member- 35 secured to the valve chest.Within the valve chest is a valve of the three-spool type, this valvebeing designated 36 and comprising end spools or heads 37 and 38yfittingthe bores 14 and a central spool 39 the/bore 15, the heads 37 and 38being con nected respectively with'the spool 39 by re-- duced' portions40 and 41. The ends of the heads 37 and 38 are hollowed out as indicatedat i2 andbuiil'er plugs 43 arranged in the a casing 12 in which suit- 26and opening into I a are connected by a of slightly larger diameterfitting 7 while the 1 and port 32.

ends of the chambers 14 limitthe throw of the valve, these extendinginto the recesses 42. The buffer plugs are laterally grooved asindicated 44 and these plugs are'also traversed by axially extendingvent. ports.

' and cush oning or aslowing down in strokes and passages 26 and 29. Theplugs are of a diameter to nearlyfill the bores 42 in the heads 37 and38, but the grooves 44; permit the ready supply and escape of fluid frombetween the ends of the valve and the buffers,

vents 45 facilitate the movements of the valve towards the buffers andby providing leak means when the valve moves out of contact with the bffers prevents too throwing when by r V the rearward stroke of thepiston (during which the partial rotation given the piston occurs) isslowed downand the interval between th I increased. Premature throwingdue to leakage past the edge of the piston when the parts are worn isalso prevented by this feature. A fluid pressure supply port 46comcentral part of the valve chest. I aving now described the structureof the port 46 and annular space it? to the left of thehead 39 and, byway'of port 17 and passage 10, tothe rear end of the piston 3 to cause aforward movement thereof. Simultaneously the front end of the cylinderis connected to exhaust by f passage 9, port 16, annular port 30, Thepiston 3 will accordingly move forward, and during its forward travel,will first overrun the port 25. This port is of such size as to permitthe supply of sufficient air to the passage 22 to substantially fillthat passage and the space in front of the head 37 of the valve with airjust about as the throwing port :24 is uncovered by the piston.Accordingly, the

. valve will be thrown over sharply on open- 28 are of mg of the port 24and by reason of the preliminary filling of the passages, and then theuncovering of the relatively large throwmg port, it is possible to get Iwhich must occur before a reversal of direction of the piston can takeplace- However the passages 24!, 25 and 27, such size and are so spacedlongi-. tudinallyrof the cylinder that the valve is not thrown until theports 24, 25 or 27, 28

' opening of the the rearward travel of are both uncovered by thepiston. lVere n0 auxiliary ports such as 25 a ployed there would beeither too early throw-" ing of the main valve with resultant loss ofpower by too prompt cutting off of the air per minute. By usingtheauxiliary ports there is no sudoenpressure drop in the rear end ofthe cylinder when the port 2% opens as the throwing additionaladvantage. After the valve 36 is moved to the position sh'ownin Fig. 2,when a suflicient pressure hasbeen admitted to the front end of thecylinder by way of port 16 and passage 9, the return stroke. of thepiston will take place, it being noted that if the piston overrunstheport 9 at theforward end of its travel, the air entrapped between thefront end of the piston and the head 5, either alone or withthe aid ofthe rebound.

nary drilling with the steel well back in the chuck, 1. e. withthedrill-heldup properly i3 9 Wlll not ordinarily be Ward stroke andfirstu'ncover the port 28 which'will transmit a sufiicient pressure to 1up the passage 23 and the spaceto the front end of the valve chestbefore the port is uncovered and accordinglywith the port27 aquick,sharp reversal of the valve 36 will take place It will ofcourse thepiston the rear end of the cylinder is connected by passage 10, port 17.groove 30, and port 33 with the exhaust. When rotation is hard the airtransmitted through port 28 would tend to throw the valve before theport- 27 is reached by the slow moving piston but'by reason of the vent45' as soon as thevalve' beginsto move. the resultant opening of thevent will give the necessary delay to permit a full rear stroke, itbeingnoted thatliveflpressure' on the'unbalanced area of the middle spoolre-' sists the valve movement. While. of course,

orts and the aorta are ssaced in-the end 28 to be embe understood thatduring 1 eral manner shown, it is possible to, inere'ase the drillingspeed of a motor of the type herein illustrated quite 20% overits speedwhen employed ,with the ordinary single throwing ports. This isobviously a most desirable improvement asprior to the pro} vision of myimproved construction a motor of the type illustrated was equal to thebest i of equal cylinder size and piston weight, and by reason of myinvention, a considerable margin of superiority over any motor. of whichI am now aware is produced.

While I have in this application specifically described one form'whichmy invention may assume in practice, it is understood that this form ofthe same is shown for purposes of illustration and that the inventionmay be modified and embodied in various other forms without departingfrom its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is: 1. In afluid pressure motor, a cylinder, a piston reciprocable therein, meansforming distributing passages communicating with said cylinder adjacentthe ends thereof, a valve controlling said passages, and means forcontrolling said valve by the fluid in the ends of the cylinder whichdirectly actuates the piston comprising throwing passages eachcommunicating with the bore of the cylinder by a smaller port nearer theend thereof and a larger port nearer the center thereof.

2. A pressure fluid motor having a cylinder, a piston therein and afluid actuated distributing valve, main and auxiliary passage meansadapted to allow communication between each end of said valve and saidcylinder, said valve being subjected to an initial pressure due to saidauxiliary means, and means for preventing said auxiliary means fromallowing a pressure to be built up great enough to throw said valve.

3. In a fluid pressure motor, a cylinder, a piston reciprocable therein,means for effecting reciprocation of said piston including a valvechest, a valve therein, buffers limiting movement of said valve, passagemeans leading from said chest and controlled by said valve for supplyingand exhausting fluid with respect to each end of said cylinder, meansfor effecting movement of said valve comprising main and auxiliarypassage means connecting said chest with said cylinder and communicatingwith the latter at longitudinally spaced points, said auxiliary passagemeans being disposed nearer the end of the cylinder and said mainpassage means being disposed nearer the center thereof, and meanscomprising passage means formed in said buffers for venting each end ofsaid valve for preventing said auxiliary passage means from allowing apressure to be built up great enough to throw said valve prior to theopening of said main passage means.

4. A pressure fluid motor having a cylinder, a piston reciprocabletherein, a fluid distribution valve, means forming main and auxiliarypassage means adapted to allow :jected to an initial iliary passagemeans, ing passage means for lsaid valve for preventing said auxiliary'means from allowing 'the pressure to'be communication between each endof" the valve and the cylinder, said valve being subpressure 'due'tosaid auxand means compr1s-' built up great enough to throw said valveprior to the opening of said main passage means.

5. In a fluid pressure motor, a cylinder, a piston reciprocable therein,means for effecting reciprocation of said piston including a valvechest, a valve therein, said valve having a recessed head, a bufferlimiting movement of said valve, passage means leading from said chestand controlled by said valve for supplying and exhausting fluid withrespect to one end of said cylinder, meansfor effecting movement of saidvalve including a passage connecting said chest with said cylinder andcommunicating with the latter by means of a main and an auxiliary portat points spaced longitudinally of the cylinder, and passage meansformed in said buffer for venting one end of said valve for preventingpremature throwing thereof, said passage means being of lesser flow areathan said 6. In a fluid pressure motor, a cylinder, a pistonreciprocable therein, means forming distributing passages communicatingwith said cylinder adjacent the ends thereof, a valve controlling saidpassages, means for controlling'said valve comprising throwing passageseach communicating with the cylinder by main and auxiliary ports ofdilferent size at points spaced longitudinally thereof, and meanscomprising vent ports for; each end of said valve for preventing saidauxiliary ports from allowing a pressure to be built up great enough tothrow said valve prior to the opening of said main throwing ports.

7 In a fluid pressure motor, a cylinder having a bore in which a pistonis reciprocable, fluid supply and exhaust means therefor includingdistribution passages leading to points adjacent the ends of saidcylinder. valve means controlling the communication of said distributionpassages with a source of fluid pressure and with exhaust including avalve chest with which said passages communicate, said valve chest alsohaving supply and exhaust ports communicating therewith, a multiplespool valve reciprocable in said chest, and means for controlling saidvalve by the fluid in the ends of the cylinder which directlyi actuatessaid piston comprising throwing passages respectively communicating withsaid chest and with the bore of said cylinder, each of said throwingpassages having communication with the bore of the cylinder at ventingeach end of auxiliary port.

y of the cylinder, the building up ofpre'ssure, during thepethecommunication at points more closely riod intermediate 'inltialcommunication and adjacent the center of the cylinder being lessrestricted communication, sufiicient' to 10 substantially lessrestricted than'at points balance the-valve. r

5 more remote therefrom and the communica- In testimony whereof I affixmy sigma tion of said passages With the cylinder and Hire. their volumebeing proportioned to permit CHARLES H. ALLEN.

